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'72 R75/5: GEN light not going out

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David Wallace
(@david-wallace)
Posts: 25
Eminent Member
Topic starter
 

1972 R75/5.  Major overhaul this past winter including new Enduralast 1 alternator and electronic VR.  A couple weeks ago the bike wouldn't start due to a dead battery.  Since that battery was 9 - 10 years old, I chocked the dead battery up to age, so I bought a new Odyssey (PC680) battery and installed it.  Then I noticed that the GEN light wasn't going completely out as the engine was brought up to higher revs.  The light definitely dims significantly but does not go completely out.  - Shouldn't it?.  Suspecting that the aged, somewhat corroded battery cables may be to blame, I bought new cables and installed them as well.  Firing up the bike, the GEN light still dims but does not go out when held at higher revs.  I hooked up a DVM and am getting a good 14.4 V with higher engine revs, but the GEN light is still glowing dimly.   Any ideas?

This topic was modified 2 months ago by Richard Whatley
 
Posted : 07/17/2022 10:40
Richard Whatley
(@wobbly)
Posts: 2255
Member
 

Several basic questions pop into my head...

• The voltage regulator controls the Gen lamp. Have you replaced the Voltage Regulator with a modern, solid state version ? If so.... Did you buy this as a separate item, or did this unit come with the Enduralast ?

• Have you ever replaced the Gen lamp bulb ? If so.... what bulb was used ?

• Is your bike fitted with the "generate even if the lamp burns out" bulb by-pass system ?

• Was an anti-oxidation compound applied to each of the connectors, terminals, fuses, bulb bases and plugs during the installation of the Enduralast ?

Thanks.

 

This post was modified 2 months ago by Richard Whatley

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 07/18/2022 06:56
David Wallace
(@david-wallace)
Posts: 25
Eminent Member
Topic starter
 

Thanks for the troubleshooting questions.

- yes, the bike has a new modern solid state VR that came with the Enduralast alternator.  (Maybe I don't have it adjusted properly?)

- gen lamp bulb has never been replaced. (should it be?)

- no, don't have a gen lamp bulb bypass.

- yes, a di-electric grease was applied to all connections touched during the rebuild.

Maybe my garage is too dark as i'm monitoring the gen light? :-/    When riding during the daylight, I don't see the orange light lit up.

I now have a basic DVM zip tied to my handlebars - what voltage reading should I be getting as I ride at a healthy rpm? (Tach isn't working, so say 40mph in 3rd gear.)

 
Posted : 07/18/2022 18:01
Joe Hall
(@joe-hall)
Posts: 41
Trusted Member
 

I replaced the OEM charging system in my 95 R100RT last year, with an Omega 600. After the conversion I soon noticed the charge light never goes completely out, maybe 90 percent; not so noticeable in daylight, but definitely noticeable at night. Then I installed a KATDASH, and it is now noticeable in daytime, and even more noticeable at night. Thankfully I have a volt meter on the RT, which assures me all is well. I have had the Omega at least 25,000 miles now and have grown used to the charge light never going completely out. When installing the Omega, I installed all the recommended extra grounds, and later install a bulb by-pass system, by Enduralast, as Richard mentioned above, but it did not make any difference.

Before the Omega, the light went all the way out, and at lower RPM. So it appears the bulb situation is just a result of the excess wattage, and the KATDASH makes it even more pronounced. I am not an electrical guy, but that's my guess.    

 
Posted : 07/18/2022 18:05
Richard Whatley
(@wobbly)
Posts: 2255
Member
 
Posted by: @david-wallace

I now have a basic DVM zip tied to my handlebars - what voltage reading should I be getting as I ride at a healthy rpm? (Tach isn't working, so say 40mph in 3rd gear.)

• It sounds like you have done everything to insure a healthy charge system. In reading Joe's response, the reaction of the bulb seems to be normal for this type alternator/VR pairing.

• I also ran the PC680 battery on 4 different R100's and I believe 14.3V was the suggested "float" voltage suggested by Odyssey. Don't trust my memory, please call them and ask. Only a limited number of VR's had adjustments for the charge voltage. If it turns out you don't have one of those adjustable models, then I don't see 0.1V "killing" anything. Odyssey themselves only suggest a specific voltage "for maximum battery life". So it's entirely possible that considering a ~7 year battery life, then the battery's longevity might be reduced by 1 month at only 0.1V difference. IOW, not really significant.

Hope this helps.

 

Additional Comment

In years gone by the "high output" alternators were the upgrade of choice because long distance riders used a lot of extra lighting and heated riding suits. This situation may have changed with the introduction of extremely LOW wattage LED lighting. Lighting IS the major load on the electrical system. If all the standard bulbs (and any accessory lighting) are converted over to LED, then probably 85-90% of the "need" for a larger alternator goes away for the average rider.

If you are faced with the choice of alternator replacement, then I urge you to mathematically look at the Wattage load versus the alternator's Wattage output. All new LED bulbs is a much cheaper and easier solution, AND will remove a huge load from the standard rectifier and wiring. The addition of the LED HL bulb alone drops the wattage from ~100W to less than 25W !!

This post was modified 2 months ago by Richard Whatley

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 07/19/2022 03:46
Joe Hall
(@joe-hall)
Posts: 41
Trusted Member
 

On more thing I'll mention, but first had to review the RT's maintenance log for accurate miles and dates; I was a 'Tanker' in the Marine Corp, and learned to keep a meticulous logbook. LOL. I bought the RT October 2020, with 25,000 miles on it. Miles are flying by, with about 34,000 I've ridden is so far. I really enjoy riding it, more than the GoldWing, which has taken a back seat to the RT.

Anyway, per the logbook, I installed the Omega in December 2020, about 30,000 miles ago. Winter had arrived, I ride year round, and wanted extra wattage for heated gear. The Omega fit the bill nicely and, without any electrical load, the volt meter stays steady at 14.2V anytime above 3000RPM. With heated pants & jacket, grips on high, and GPS, it never drops below 13V, at 3000RPM and up. With the OEM system, under same conditions, it struggled to maintain 12V, and often dipped a bit below; I installed a headlight switch as a temporary measure, but not needed with the Omega. 

The thing I was gonna mention: April 2021, with 8000 miles on the Omega, the volt meter needle began to flicker a bit. That was just before I was to leave for a trip to Florida. So, in desperation, I replaced the higher output VR with the bike's original VR. I replaced the 'wet' battery with a Duracell DURAGM-16, mainly to get rid of the wet battery, but also to eliminate possibility the charging issue was battery related. That was 15 months and 22,000 miles ago, and both are still in the RT and doing well. So it appears, if the HO version VR fails, the OEM version works just fine, at least it does with the Omega. 

In closing, I'll mention an old GoldWing riding friend was murdered last week on his GoldWing in a hit and run crash. May he Rest In Peace. Good luck, and be careful out there!  

  

 
Posted : 07/19/2022 07:08
David Wallace
(@david-wallace)
Posts: 25
Eminent Member
Topic starter
 

@joe-hall    Joe  -    Thanks for the info.  And condolences on the loss of your Gold Wing buddy.

 
Posted : 07/19/2022 18:26
Joe Hall reacted
Richard Whatley
(@wobbly)
Posts: 2255
Member
 

Very sincere condolences on your loss, Joe.

 

The OEM voltage regulator is a very nice piece of kit, well designed, very robust and well constructed. One of the differences that make them hold up so well is the way Airheads are ridden. Whereas many bikes spend their life making short trips around town, with the large draw of the starter and then short rides punctuated by low RPM for multiple traffic stops, the Airhead typically cranks and then runs at constant RPM road speeds for hours. 

The Achille's heal of the Bosch VR is that it is mechanical in nature and contains electrical contacts. If these same contacts were in the ignition system, then we would call them "points". And like points, these contacts have a finite life expectancy. No one expects ignition points to last 20 years, and yet the vast majority of Airhead riders are riding around on the same set of points inside their OEM voltage regulators at 40 years !

That's why I recommend replacement with a modern, Solid State regulator. These transistorized versions have no points, springs or moving parts to wear-out or work themselves out of adjustment. The OEM Bosch unit was excellent, but calendar-wise, its life expectancy is simply over. 

This post was modified 2 months ago by Richard Whatley

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 07/20/2022 05:02
Joe Hall reacted

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